it's been less than a year since president obama himself dropped his opposition to gay marriage in that interview with our colleague, robin roberts. and now, even some prominent republicans are settling on the same position. >> and, rick, you study these political poll lines. what is the trending telling us right now? >> it is moving so fast. in 2004, during george w. bush's re-election, we asked in a poll if gay marriage should be legal. and only 32% said yes. this month, that number is up to 58%. that's a tectonic shift. >> rick klein, with the bigger picture, as always. rick, thank you. >>> we turn overseas to the vatican, where pope francis celebrated his first palm sunday mass, to begin the holy week leading up to easter. from the steps of st. peter's, he urged the crowd of worshippers to be humble and young at heart. he toured the square in his popemobile, open to the crowd, despite the concern of his security detail. kissing babies and shaking hands there. >>> in rome tomorrow, everyone watching something else. italy's high court will once again determine the fate of amanda knox.